Semiconductor device having optical fuse and electrical fuse

ABSTRACT

A semiconductor device includes a plurality of first chips, a second chip that controls the first chips, and internal wiring that connects the first chips and the second chip. The first chips each include: an optical fuse; a first latch circuit that retains information on the optical fuse; a second latch circuit that retains information on an electrical fuse, the information being supplied from the second chip through the internal wiring; and a select circuit that selects the information retained in either one of the first and second latch circuits. A redundancy determination signal is generated from the information selected. The information on the electrical fuse is transferred from the second chip to the first chips through the internal wiring.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a semiconductor device, and moreparticularly to a semiconductor device in which defective memory cellscan be replaced with redundant cells.

2. Description of Related Art

Semiconductor memories typified by a DRAM (Dynamic Random Access Memory)include a large number of memory cells, some of which inevitably becomedefective due to manufacturing conditions and other factors. In order toship such semiconductor memories as conforming products, the redundancyrepair technique of replacing defective memory cells with redundantcells is needed.

According to the redundancy repair technique, a semiconductor memory ina wafer state is initially subjected to an operation test to detect theaddresses of defective memory cells (defect addresses). The detectedaddresses are programmed into optical fuses in the semiconductor memory.Optical fuses are fuses that can be blown by irradiation of a laser beamor the like. Since blown optical fuses cannot be restored to aconducting state again, it is possible to store information in anonvolatile and irreversible manner. When access is requested to theaddresses programmed in the optical fuses, redundant cells (alternativecells) are accessed instead of the defective memory cells, whereby theaddresses are repaired.

Memory cell defects occur mainly in the wafer stage (manufacturing stepsfor forming a plurality of circuits on a wafer; so-called front-endprocesses). Most defects are therefore repaired by replacement usingoptical fuses. However, new defects can occur after the replacementusing optical fuses, in back-end processes including assembly. Forexample, new defects may occur due to a thermal load during packaging.It is not possible to repair such defects by using the optical fuses.

As a solution to the problem, Japanese Patent Application Laid-Open No.2002-25289 (Patent Document 1) proposes a semiconductor device that canimplement both the replacement using optical fuses and replacement usingelectrical fuses. The semiconductor device described in Patent Document1, however, has had the problem that the need to provide both opticalfuses and electrical fuses in a single chip increases the die size.

Japanese Patent Application Laid-Open No. 2007-328914 (Patent Document2) proposes a method of storing post-packaging defective addresses of avolatile memory (first semiconductor device) into a nonvolatile memory(second semiconductor device) which is mounted on the same modulesubstrate, and loading the defective addresses from the secondsemiconductor device to the first semiconductor device at startup.According to such a method, the volatile memory to be repaired, such asa DRAM, need not include electrical fuses. It is therefore possible tosuppress the increase in die size.

According to the method described in Patent Document 2, however,defective addresses are loaded through external terminals of the firstsemiconductor device. The inventors have recognized that it interferedwith an initialization operation between a memory controller and thememory module impossible during the loading period. An event thereforearises since it takes time to start up the memory module.

SUMMARY

A semiconductor memory may be composed of a back-end unit includingmemory cores and a front-end unit including an interface circuit. A typeof semiconductor device has recently been proposed in which the back-endunit and the front-end unit are separated into different chips (corechip and interface chip), which are stacked into a single package(sealed with resin or the like). In such a type of semiconductor device,the interface chip where the front-end unit is integrated may have thefunction of electrical fuses, and the information on the electricalfuses may be transferred from the interface chip to the core chip. Thiscan prevent an increase in the area of the core chip where the back-endunit is integrated, and eliminate the need for the operation of loadingdefective addresses through external terminals of the semiconductordevice. That is, it is possible to avoid an increase in area because thecore chip incorporates electrical fuses for repairing post-packagingdefectives of memory cells included in the core chip. The presentinvention has been achieved based on such technical findings.

In one embodiment, there is provided a semiconductor device thatincludes an external terminal; a plurality of first chips each of whichincludes a plurality of memory cells; a second chip that communicateswith outside of the semiconductor device through the external terminaland controls the plurality of first chips; and a plurality of internalwirings connected between the first chips and the second chip, each ofthe internal wirings including a plurality of through electrodes, eachof the through electrodes penetrating through a corresponding one of thefirst chips, wherein the plurality of first chips communicates with theoutside of the semiconductor device through the second chip withoutdirectly communicating with the outside, the second chip includes anelectrical fuse, and each of the first chips further includes: anoptical fuse; a first latch circuit that stores information on theoptical fuse; a second latch circuit that stores information on theelectrical fuse supplied from the second chip through the internalwirings; a select circuit that selects one of the information stored inthe first and second latch circuits; and a first control circuit thatgenerates a redundancy determination signal based on the informationselected by the select circuit.

In another embodiment, there is provided a semiconductor device thatincludes an external signal terminal; a plurality of core chips each ofwhich includes a plurality of memory cells, the core chips being notdirectly connected to the external signal terminal; and an interfacechip connected to the external signal terminal and controls theplurality of core chips, wherein the core chips and the interface chipare stacked on one another, the core chips are electrically connected tothe interface chip via through electrodes, each of the throughelectrodes penetrating through a corresponding one of the core chips,the interface chip includes an electrical fuse storing an address of adefective memory cell included in any of the core chips, each of thecore chips further includes: a redundant cell that replaces thedefective memory cell; an optical fuse storing the address of thedefective memory cell; a select circuit that selects one of an addressread from the optical fuse and the electrical fuse; and an accesscontrol circuit that accesses the redundant cell instead of thedefective memory cell in response to a request for access to the addressselected by the select circuit.

According to the present invention, the information on the electricalfuse is transferred from the second chip to the first chips via thethrough electrodes. This eliminates the need to provide electrical fuseson the first chips. The disuse of the external terminal in transferringthe information prevents an increase in the startup time of thesemiconductor device.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill be more apparent from the following description of certainpreferred embodiments taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a block diagram for explaining the principle of the presentinvention;

FIG. 2 is a schematic cross-sectional view provided to explain thestructure of a semiconductor device 10 according to a preferredembodiment of the present invention;

FIGS. 3A to 3C are diagrams showing the various types of through siliconvias TSV provided in a core chip;

FIG. 4 is a cross-sectional view illustrating the structure of thethrough silicon via TSV of the type shown in FIG. 3A;

FIG. 5 is a block diagram illustrating the circuit configuration of thesemiconductor device 10;

FIG. 6 is a flowchart for explaining the method of replacing defectivecells included in the core chips CC0 to CC7;

FIG. 7 is a flowchart for explaining operations of steps S15 and S16shown in FIG. 6 in more detail;

FIG. 8 is a flowchart for explaining an operation of loading replacementdata programmed in an electrical fuse circuit 83;

FIG. 9 is a block diagram showing a configuration of the electrical fusecircuit 83 in more detail;

FIG. 10 is a block diagram showing a configuration of a defectiveaddress latch circuit 56 in more detail;

FIG. 11 is another block diagram showing the configuration of thedefective address latch circuit 56 in more detail;

FIG. 12 is a block diagram showing the configuration of the electricalfuse circuit 83 and the defective address latch circuit 56 in moredetail;

FIG. 13 is a diagram for explaining a relationship between order ofselection of optical fuse circuits 55 and order of selection of theelectrical fuse circuit 83;

FIG. 14 is a circuit diagram showing an example of an address comparisoncircuit 51 a and a select circuit 56 e; and

FIG. 15 is a circuit diagram showing another example of the addresscomparison circuit 51 a and the select circuit 56 e.

DETAILED DESCRIPTION OF THE EMBODIMENT

A representative example of the technical concept of the presentinvention for solving the events will be described below. It will beunderstood that what is claimed by the present invention is not limitedto such a technical concept and is set forth in the claims of thepresent invention.

The technical concept of the semiconductor device according to thepresent invention is to stack a plurality of core chips where theback-end unit is integrated and an interface chip where the front-endunit is integrated, provide optical fuses (laser fuses) on the core-chipside, provide electrical fuses on the interface-chip side, and transferinformation on the electrical fuses to the core chips via throughelectrodes. Since the electrical fuses need not be provided on thecore-chip side, it is possible to prevent an increase in the area of thecore chips. Since the information on the electrical fuses is transferredto the core chips via the through electrodes, there is no interferencewith an initialization operation that the interface chip needs toperform with a memory controller outside the semiconductor devicethrough external terminals of the semiconductor device.

FIG. 1 is a block diagram for explaining the principle of the presentinvention.

As shown in FIG. 1, the semiconductor device according to the presentinvention includes a plurality of first chips 100 and a second chip 200.The plurality of first chips 100 have the same circuit configuration,each including a memory cell array 110 which includes a plurality ofmemory cells. The first chips 100 perform communication through thesecond chip 200 without directly communicating with outside of thesemiconductor device, and therefore are not directly connected toexternal terminals 300. The plurality of first chips 100 and the secondchip 200 are connected to each other through respective correspondinginternal wirings 400. The internal wirings 400 include throughelectrodes that penetrate through the substrates of the respectivecorresponding first chips 100.

The second chip 200 is a chip that controls the plurality of first chips100, and is directly connected to the external terminals 300 for thesake of communication with outside of the semiconductor device. Thesecond chip 200 includes an access control circuit 210, an electricalfuse 220, and a flag fuse 230. The flag fuse 230 has the same structureas that of the electrical fuse 220, and contains first flag informationFL1 which indicates whether or not information is set in the electricalfuse 220. Electrical fuse information AF programmed in the electricalfuse 220 and the flag information FL1 programmed in the flag fuse 230are supplied to an output circuit 240. The output circuit 240 functionsto supply the electrical fuse information AF and the flag informationFL1 to the first chips 100 through the internal wirings 400.

The first chips 100 each include an optical fuse 120 and a first latchcircuit 101 that retains optical fuse information LF programmed in theoptical fuse 120. The first chips 100 each further include a flag fuse130. The flag fuse 130 has the same structure as that of the opticalfuse 120, and contains second flag information FL2 which indicateswhether optical fuse information LF is set in the optical fuse 120. Thesecond flag information FL2 is latched by a fourth latch circuit 104.

The electrical fuse information AF and the first flag information FL1,transferred from the second chip 200 through the internal wirings 400,are received by an input circuit 140 which is arranged in each firstchip 100. The electrical fuse information AF and the first flaginformation FL1 received are latched by a second latch circuit 102 and athird latch circuit 103, respectively.

The optical fuse information LF latched in the first latch circuit andthe electrical fuse information AF latched in the second latch circuitare supplied to a select circuit 151 which is included in a controlcircuit 150. The select circuit 151 is a circuit that selects either oneof the optical fuse information LF and the electrical fuse informationAF. The selection is made based on the first and second flag informationFL1 and FL2 latched in the third and fourth latch circuits 103 and 104.The optical fuse information LF or electrical fuse information AFselected is supplied to an address comparison circuit 152 which isincluded in the control circuit 150.

The address comparison circuit 152 is a circuit that compares theoptical fuse information LF or electrical fuse information AF selectedwith an access-requested address ADD. If the two coincide, the addresscomparison circuit 152 activates a redundancy determination signal HIT.When the redundancy determination signal HIT is activated, an accesscontrol circuit 160 stops accessing the memory cell array 110 andaccesses a redundancy array 170 including redundant cells instead. As aresult, redundant cells are accessed instead of defective memory cells.

Preferred embodiments of the present invention will be explained belowin detail with reference to the accompanying drawings.

FIG. 2 is a schematic cross-sectional view provided to explain thestructure of a semiconductor device 10 according to the preferredembodiment of the present invention.

As shown in FIG. 2, the semiconductor device 10 according to thisembodiment has the structure where 8 core chips CC0 to CC7 that have thesame function and structure and are manufactured using the samemanufacture mask, an interface chip IF that is manufactured using amanufacture mask different from that of the core chips and an interposerIP are laminated. The core chips CC0 to CC7 and the interface chip IFare semiconductor chips using a silicon substrate and are electricallyconnected to adjacent chips in a vertical direction through pluralthrough silicon vias TSV penetrating the silicon substrate. Meanwhile,the interposer IP is a circuit board that is made of a resin, and pluralexternal terminals (solder balls) SB are formed in a back surface IPb ofthe interposer IP.

Each of the core chips CC0 to CC7 is a semiconductor chip which consistsof circuit blocks other than a so-called front end unit (front endfunction) performing a function of an interface with an external devicethrough an external terminal among circuit blocks included in a 1 GbDDR3 (Double Data Rate 3)-type SDRAM (Synchronous Dynamic Random AccessMemory). The SDRAM is a well-known and common memory chip that includesthe front end unit and a so-called back end unit having a plural memorycells and accessing to the memory cells. The SDRAM operates even as asingle chip and is capable to communicate directly with a memorycontroller. That is, each of the core chips CC0 to CC7 is asemiconductor chip where only the circuit blocks belonging to the backend unit are integrated in principle. As the circuit blocks that areincluded in the front end unit, a parallel-serial converting circuit(data latch circuit) that performs parallel/serial conversion oninput/output data between a memory cell array and a data input/outputterminal and a DLL (Delay Locked Loop) circuit that controlsinput/output timing of data are exemplified, which will be described indetail below. The interface chip IF is a semiconductor chip in whichonly the front end unit is integrated. Accordingly, an operationfrequency of the interface chip is higher than an operation frequency ofthe core chip. Since the circuits that belong to the front end unit arenot included in the core chips CC0 to CC7, the core chips CC0 to CC7cannot be operated as the single chips, except for when the core chipsare operated in a wafer state for a test operation in the course ofmanufacturing the core chips. The interface chip IF is needed to operatethe core chips CC0 to CC7. Accordingly, the memory integration of thecore chips is denser than the memory integration of a general singlechip. The interface chip IF has a front end function for communicatingwith the external device at a first operation frequency, and the pluralcore chips CC0 to CC7 have a back end function for communicating withonly the interface chip IF at a second operation frequency lower thanthe first operation frequency. Accordingly, each of the plural corechips CC0 to CC7 includes a memory cell array that stores pluralinformation, and a bit number of plural read data for each I/O (DQ) thatare supplied from the plural core chips CC0 to CC7 to the interface chipIF in parallel is plural and associated with a one-time read commandprovided from the interface chip IF to the core chips. In this case, theplural bit number corresponds to a prefetch data number to bewell-known.

The interface chip IF functions as a common front end unit for the eightcore chips CC0 to CC7. Accordingly, all external accesses are performedthrough the interface chip IF and inputs/outputs of data are alsoperformed through the interface chip IF. In this embodiment, theinterface chip IF is disposed between the interposer IP and the corechips CC0 to CC7. However, the position of the interface chip IF is notrestricted in particular, and the interface chip IF may be disposed onthe core chips CC0 to CC7 and may be disposed on the back surface IPb ofthe interposer IP. When the interface chip IF is disposed on the corechips CC0 to CC7 in a face-down manner or is disposed on the backsurface IPb of the interposer IP in a face-up manner, the throughsilicon via TSV does not need to be provided in the interface chip IF.The interface chip IF may be disposed to be interposed between the twointerposers IP.

The interposer IP functions as a rewiring substrate to increase anelectrode pitch and secures mechanical strength of the semiconductordevice 10. That is, an electrode 91 that is formed on a top surface IPaof the interposer IP is drawn to the back surface IPb via a through-holeelectrode 92 and the pitch of the external terminals SB is enlarged bythe rewiring layer 93 provided on the back surface IPb. In FIG. 2, onlythe two external terminals SB are shown. In actuality, however, three ormore external terminals are provided. The layout of the externalterminals SB is the same as that of the DDR3-type SDRAM that isdetermined by the regulation. Accordingly, the semiconductor memorydevice can be treated as one DDR3-type SDRAM from the externalcontroller.

As shown in FIG. 2, a top surface of the uppermost core chip CC0 iscovered by an NCF (Non-Conductive Film) 94 and a lead frame 95. Gapsbetween the core chips CC0 to CC7 and the interface chip IF are filledwith an underfill 96 and surrounding portions of the gaps are covered bya sealing resin 97. Thereby, the individual chips are physicallyprotected.

When most of the through silicon vias TSV provided in the core chips CC0to CC7 are two-dimensionally viewed from a lamination direction, thatis, viewed from an arrow A shown in FIG. 2, the through silicon vias TSVare short-circuited from the through silicon vias TSV of other layersprovided at the same position. That is, as shown in FIG. 3A, thevertically disposed through silicon vias TSV1 that are provided at thesame position in plain view are short-circuited, and one wiring line isconfigured by the through silicon via TSV1. The through silicon via TSV1that are provided in the core chips CC0 to CC7 are connected to internalcircuits 4 in the core chips, respectively. Accordingly, input signals(command signal, address signal, etc.) that are supplied from theinterface chip IF to the through silicon vias TSV1 shown in FIG. 3A arecommonly input to the internal circuits 4 of the core chips CC0 to CC7.Output signals (data etc.) that are supplied from the core chips CC0 toCC7 to the through silicon via TSV1 are wired-ORed and input to theinterface chip IF.

Meanwhile, as shown in FIG. 3B, the a part of through silicon vias TSVare not directly connected to the through silicon via TSV2 of otherlayers provided at the same position in plain view but are connected tothe through silicon via TSV2 of other layers through the internalcircuits 5 provided in the core chips CC0 to CC7. That is, the internalcircuits 5 that are provided in the core chips CC0 to CC7 arecascade-connected through the through silicon via TSV2. This kind ofthrough silicon via TSV2 is used to sequentially transmit predeterminedinformation to the internal circuits 5 provided in the core chips CC0 toCC7. As this information, layer address information to be describedbelow is exemplified.

Another through silicon via TSV group is short-circuited from thethrough silicon vias TSV of other layer provided at the differentposition in plan view, as shown in FIG. 3C. With respect to this kind ofthrough silicon via TSV group 3, internal circuits 6 of the core chipsCC0 to CC7 are connected to the through silicon via TSV3 a provided atthe predetermined position P in plain view. Thereby, information can beselectively input to the internal circuits 6 provided in the core chips.As this information, defective chip information to be described below isexemplified.

As such, as types of the Through silicon vias TSV provided in the corechips CC0 to CC7, three types (through silicon via TSV1 to throughsilicon via TSV3) shown in FIGS. 3A to 3C exist. As described above,most of the Through silicon vias TSV are of a type shown in FIG. 3A, andan address signal, a command signal, and a clock signal are suppliedfrom the interface chip IF to the core chips CC0 to CC7, through thethrough silicon via TSV1 of the type shown in FIG. 3A. Read data andwrite data are input to and output from the interface chip IF throughthe through silicon via TSV1 of the type shown in FIG. 2A. Meanwhile,the through silicon via TSV2 and through silicon via TSV3 of the typesshown in FIGS. 3B and 3C are used to provide individual information tothe core chips CC0 to CC7 having the same structure.

FIG. 4 is a cross-sectional view illustrating the structure of thethrough silicon via TSV1 of the type shown in FIG. 3A.

As shown in FIG. 4, the through silicon via TSV1 is provided topenetrate a silicon substrate 180 and an interlayer insulating film 181provided on a surface of the silicon substrate 180. Around the throughsilicon via TSV1, an insulating ring 182 is provided. Thereby, thethrough silicon via TSV1 and a transistor region are insulated from eachother. In an example shown in FIG. 4, the insulating ring 182 isprovided double. Thereby, capacitance between the through silicon viaTSV1 and the silicon substrate 180 is reduced.

An end 183 of the through silicon via TSV1 at the back surface of thesilicon substrate 180 is covered by a back surface bump 184. The backsurface bump 184 is an electrode that contacts a surface bump 185provided in a core chip of a lower layer. The surface bump 185 isconnected to an end 186 of the through silicon via TSV1, through pluralpads P0 to P3 provided in wiring layers L0 to L3 and plural through-holeelectrodes TH1 to TH3 connecting the pads to each other. Thereby, thesurface bump 185 and the back surface bump 184 that are provided at thesame position in plain view are short-circuited. Connection withinternal circuits (not shown in the drawings) is performed throughinternal wiring lines (not shown in the drawings) drawn from the pads P0to P3 provided in the wiring layers L0 to L3.

FIG. 5 is a block diagram illustrating the circuit configuration of thesemiconductor device 10.

As shown in FIG. 5, the external terminals that are provided in theinterposer IP include clock terminals 11 a and 11 b, an clock enableterminal 11 c, command terminals 12 a to 12 f, an address terminal 13 ato 13 c, a data input/output terminal 14, data strobe terminals 15 a and15 b, a calibration terminal 16, power supply terminals 17 a and 17 b,and a data mask terminal 18. All of the external terminals other thanthe power supply terminals 17 a and 17 b are connected to the interfacechip IF and are not directly connected to the core chips CC0 to CC7.

First, a connection relationship between the external terminals and theinterface chip IF and the circuit configuration of the interface chip IFwill be described.

The clock terminals 11 a and 11 b are supplied with external clocksignals CK and /CK, respectively, and the clock enable terminal 11 c issupplied with a clock enable signal CKE. The external clock signals CKand /CK and the clock enable signal CKE are supplied to a clockgenerating circuit 21 provided in the interface chip IF. A signal where“/” is added to a head of a signal name in this specification indicatesan inversion signal of a corresponding signal or a low-active signal.Accordingly, the external clock signals CK and /CK are complementarysignals. The clock generating circuit 21 generates an internal clocksignal ICLK, and the generated internal clock signal ICLK is supplied tovarious circuit blocks in the interface chip IF and is commonly suppliedto the core chips CC0 to CC7 through the through silicon vias TSV.

A DLL circuit 22 is included in the interface chip IF and aninput/output clock signal LCLK is generated by the DLL circuit 22. Theinput/output clock signal LCLK is supplied to an input/output buffercircuit 23 included in the interface chip IF. A DLL function is used tocontrol the front end unit by using the signal LCLK synchronized with asignal of the external device, when the semiconductor device 10communicates with the external device. Accordingly, DLL function is notneeded for the core chips CC0 to CC7 as the back end.

The command terminals 12 a to 12 f are supplied with a chip selectsignal /CS, a row-address strobe signal /RAS, a column address strobesignal /CAS, a write enable signal /WE, an on-die termination signalODT, and a reset signal /RESET. These command signals are supplied to acommand input buffer 31 that is provided in the interface chip IF. Thecommand signals supplied to the command input buffer 31 are furthersupplied to a control logic 32. The control logic 32 includes a latencycontroller 32 a and a command decoder 32 b. The control logic 32 is acircuit that holds, decodes, and counts the command signals insynchronization with the internal clock ICLK and generates variousinternal commands ICMD. The generated internal command ICMD is suppliedto the various circuit blocks in the interface chip IF and is commonlysupplied to the core chips CC0 to CC7 through a TSV buffer 34 and thethrough silicon vias TSV.

The address terminal 13 a is a terminal to which a bank address BA0 toBA2 is supplied. The address terminal 13 b is a terminal to which anaddress signal A0 to A(N−3) is supplied. The address terminal 13C is aterminal to which an address signal AN to A(N−2) is supplied. Thesupplied address signals A0 to AN (A15) and BA0 to BA2 are supplied toan address input buffer 41 which is arranged in the interface chip IF.The output of the address input buffer 41 is supplied to the controllogic 32 and a layer address buffer 48. The layer address buffer 48functions to supply a layer address (layer information) EXA to the corechips CC0 to CC7 in common through the through silicon vias TSV. When inmode register setting, the address signal A0 to AN (A15) supplied to thecontrol logic 32 is supplied to a mode register 42 which is arranged inthe interface chip IF. The bank address BA0 to BA2 is decoded by thecontrol logic 32, and the resulting bank select signal is supplied to aFIFO circuit 25. The reason is that bank selection on write data isperformed inside the interface chip IF.

The data input/output terminal 14 is used to input/output read data orwrite data DQ0 to DQ7. The data strobe terminals 15 a and 15 b areterminals that are used to input/output strobe signals DQS and /DQS. Thedata mask terminal 18 is a terminal to which a data mask signal DM issupplied. The data input/output terminal 14, the data strobe terminals15 a and 15 b, and the data mask terminal 18 are connected to theinput/output buffer circuit 23 provided in the interface chip IF. Theinput/output buffer circuit 23 includes an input buffer IB and an outputbuffer OB, and inputs/outputs the read data or the write data DQ0 to DQ7and the strobe signals DQS and /DQS in synchronization with theinput/output clock signal LCLK supplied from the DLL circuit 22. If aninternal on-die termination signal IODT is supplied from the controllogic 32, the input/output buffer circuit 23 causes the output buffer OBto function as a termination resistor. An impedance code DRZQ issupplied from the calibration circuit 24 to the input/output buffercircuit 23. Thereby, impedance of the output buffer OB is designated.

The calibration circuit 24 includes a replica buffer RB that has thesame circuit configuration as the output buffer OB. If the calibrationsignal ZQC is supplied from the control logic 32, the calibrationcircuit 24 refers to a resistance value of an external resistor (notshown in the drawings) connected to the calibration terminal 16 andperforms a calibration operation. The calibration operation is anoperation for matching the impedance of the replica buffer RB with theresistance value of the external resistor, and the obtained impedancecode DRZQ is supplied to the input/output buffer circuit 23. Thereby,the impedance of the output buffer OB is adjusted to a desired value.

The input/output buffer circuit 23 is connected to a FIFO circuit 25.The FIFO circuit 25 includes a FIFO circuit unit (not shown in thedrawings) that realizes a FIFO function which operates by latencycontrol realizing the well-known DDR function and a multiplexer (notshown in the drawings). The input/output buffer circuit 23 convertsparallel read data, which is supplied from the core chips CC0 to CC7,into serial read data, and converts serial write data, which is suppliedfrom the input/output buffer, into parallel write data. Accordingly, thedata latch circuit 25 and the input/output buffer circuit 23 areconnected in serial and the FIFO circuit 25 and the core chips CC0 toCC7 are connected in parallel. Parallel write data output from the FIFOcircuit 25 is supplied to the core chips CC0 to CC7 through a TSV buffer26. Parallel read data output from the core chips CC0 to CC7 is suppliedto the FIFO circuit 25 through the TSV buffer 26. In this embodiment,each of the core chips CC0 to CC7 is the back end unit of the DDR3-typeSDRAM and a prefetch number is 8 bits. The FIFO circuit 25 and eachbanks of the core chips CC0 to CC7 are connected respectively, and thenumber of banks that are included in each of the core chips CC0 to CC7is 8. Accordingly, connection of the FIFO circuit 25 and the core chipsCC0 to CC7 becomes 64 bits (8 bits×8 banks) for each DQ.

Parallel data, not converted into serial data, is basically transferredbetween the FIFO circuit 25 and the core chips CC0 to CC7. That is, in acommon SDRAM (in the SDRAM, a front end unit and a back end unit areconstructed in one chip), between the outside of the chip and the SDRAM,data is input/output in serial (that is, the number of data input/outputterminals is one for each DQ). However, in the core chips CC0 to CC7, aninput/output of data between the interface chip IF and the core chips isperformed in parallel. This point is the important difference betweenthe common SDRAM and the core chips CC0 to CC7. However, all of theprefetched parallel data do not need to be input/output using thedifferent through silicon vias TSV, and partial parallel/serialconversion may be performed in the core chips CC0 to CC7 and the numberof through silicon vias TSV that are needed for each DQ may be reduced.For example, all of data of 64 bits for each DQ do not need to beinput/output using the different through silicon vias TSV, and 2-bitparallel/serial conversion may be performed in the core chips CC0 to CC7and the number of through silicon vias TSV that are needed for each DQmay be reduced to ½ (32).

To the FIFO circuit 25, a function for enabling a test in an interfacechip unit is added. The interface chip does not have the back end unit.For this reason, the interface chip cannot be operated as a single chipin principle. However, if the interface chip IF never operates as thesingle chip, an operation test of the interface chip IF in a wafer statemay not be performed. This means that the semiconductor memory device 10cannot be tested in case an assembly process of the interface chip andthe plural core chips is not executed, and the interface chip is testedby testing the semiconductor memory device 10. In this case, when adefect that cannot be recovered exists in the interface chip, the entiresemiconductor memory device 10 is not available. In consideration ofthis point, in this embodiment, a portion of a pseudo back end unit fora test is provided in the FIFO circuit 25, and a simple memory functionis enabled at the time of a test.

The power supply terminals 17 a and 17 b are terminals to which powersupply potentials VDD and VSS are supplied, respectively. The powersupply terminals 17 a and 17 b are connected to a power-on detectingcircuit 43 provided in the interface chip IF and are also connected tothe core chips CC0 to CC7 through the through silicon vias TSV. Thepower-on detecting circuit 43 detects the supply of power. On detectingthe supply of power, the power-on detecting circuit 43 activates a layeraddress control circuit 45 on the interface chip IF.

The layer address control circuit 45 changes a layer address due to theI/O configuration of the semiconductor device 10 according to thepresent embodiment. As described above, the semiconductor device 10includes 8 data input/output terminals 14. Thereby, a maximum I/O numbercan be set to 8 bits (DQ0 to DQ7). However, the I/O number is not fixedto 8 bits and, for example, may be set to 4 bits (DQ0 to DQ3). Theaddress allocation is changed according to the I/O number and the layeraddress is also changed. The layer address control circuit 45 changesthe address allocation according to the I/O number and is commonlyconnected to the core chips CC0 to CC7 through the Through silicon viasTSV.

The interface chip IF is also provided with a layer address settingcircuit 44. The layer address setting circuit 44 is connected to thecore chips CC0 to CC7 through the through silicon vias TSV. The layeraddress setting circuit 44 is cascade-connected to the layer addressgenerating circuit 46 of the core chips CC0 to CC7 using the throughsilicon via TSV2 of the type shown in FIG. 3B, and reads out the layeraddresses set to the core chips CC0 to CC7 at testing.

The interface chip IF is also provided with a defective chip informationholding circuit 33. When a defective core chip that does not normallyoperates is discovered after an assembly, the defective chip informationholding circuit 33 holds its chip number. The defective chip informationholding circuit 33 is connected to the core chips CC0 to CC7 through thethrough silicon vias TSV. The defective chip information holding circuit33 is connected to the core chips CC0 to CC7 while being shifted, usingthe through silicon via TSV3 of the type shown in FIG. 3C.

The interface chip IF further includes an electrical fuse circuit 83.The electrical fuse circuit 83 is a circuit that stores information thatis needed to replace defects found after assembly with redundancycircuits. The information to be stored in the electrical fuse circuit 83includes at least information on defects of the through silicon vias TSVand information on defects of the memory cells in the core chips CC0 toCC7. The TSV buffers 26 and 34 can replace the defective through siliconvias TSV with other through silicon vias TSV for repair. Since suchrepair is not directly related to the gist of the present invention,detailed description thereof will thus be omitted. The defective throughsilicon vias TSV are detected by using a DFT circuit 81, and programmedinto the electrical fuse circuit 83.

The electrical fuse circuit 83 stores row addresses that represent wordlines to be replaced or column addresses that represent bit lines to bereplaced. Redundant word lines or redundant bit lines included in thecorresponding core chips CC0 to CC7 are used as replacing redundant wordlines or redundant bit lines.

The information stored in the electrical fuse circuit 83 includesinformation on defective addresses of memory cells, which is seriallyconverted into serial data ALD by a serializer 84 before transferred tothe core chips CC0 to CC7 via through silicon vias TSV. As shown in FIG.5, defective addresses are transferred by using a plurality of throughsilicon vias TSV in parallel so as to avoid transfer defect due todefects of the through silicon vias TSV themselves. Other signals thatuse irreplaceable through silicon vias TSV, such as the layer addressEXA and a determination signal P/F to be described later, also use aplurality of through silicon vias TSV in parallel.

The electrical fuse circuit 83 is programmed by an analysis circuit 82.The analysis circuit 82 is activated by a signal FENT which is theoutput of a DFT circuit 37. The analysis circuit 82 analyzes the patternof occurrence of defective memory cells based on addresses supplied fromthe control logic 32 and the determination signal P/F supplied from thecore chips CC0 to CC7. The analysis is intended to identify a patternthat allows most efficient replacement when replacing defective memorycells in units of word lines or bit lines. This means that the addressesstored in the electrical fuse circuit 83 are not in units of memorycells but in units of word lines or bit lines. The replacement in unitsof word lines or bit lines is performed during manufacturing when thecore chips CC0 to CC7 are in a wafer state. The electrical fuse circuit83 uses redundant word lines or bit lines that remain unused by thereplacement in the wafer state. The analysis circuit 82 is thus a failmemory repair analyzer.

The information programmed in the electrical fuse circuit 83 is read byusing a load circuit 85. The load circuit 85 reads the informationprogrammed in the electrical fuse circuit 83 and generates timingsignals ALFL and ALCK, thereby functioning to synchronize the serializer84 with the core chips CC0 to CC7.

The above description is the outline of the connection relationshipbetween the external terminals and the interface chip IF and the circuitconfiguration of the interface chip IF. Next, the circuit configurationof the core chips CC0 to CC7 will be described.

As shown in FIG. 5, memory cell arrays 50 that are included in the corechips CC0 to CC7 having the back end function are divided into eightbanks. A bank is a unit that can individually receive a command. Thatis, the individual banks can be independently and nonexclusivelycontrolled. From the outside of the semiconductor device 10 (an outsidecontroller which controls the semiconductor device 10), each back can beindependently accessed. For example, a part of the memory cell array 50belonging to the bank 1 and another part of the memory cell array 50belonging to the bank 2 are controlled nonexclusively. That is, wordlines WL and bit lines BL corresponding to each banks respectively areindependently accessed at same period by different commands one another.For example, while the bank 1 is maintained to be active (the word linesand the bit lines are controlled to be active), the bank 2 can becontrolled to be active. However, the external terminals (for example,plural control terminals and plural I/O terminals) of the semiconductormemory device 10 are shared. In the memory cell array 50, the pluralword lines WL and the plural bit lines BL intersect each other, andmemory cells MC are disposed at intersections thereof (in FIG. 5, onlyone word line WL, one bit line BL, and one memory cell MC are shown).

The memory cell array 50 includes a row redundancy array 50 a and acolumn redundancy array 50 b. The row redundancy array 50 a includesredundant cells RMC that are connected to a plurality of redundant wordlines RWL. The column redundancy array 50 b includes redundant cells RMCthat are connected to a plurality of redundant bit lines RBL. The rowredundancy array 50 a is accessed as an alternative if anaccess-requested memory cell belongs to a defective word line. Thecolumn redundancy array 50 b is accessed as an alternative if anaccess-requested memory cell belongs to a defective bit line. Suchalternative accesses are made when an access is requested to theaddresses that are stored in the foregoing electrical fuse circuit 83 oroptical fuse circuits 55 and 57 to be described later.

The word lines WL are selected by a row decoder 51. The bit lines BL areconnected to corresponding sense amplifiers SA in a sense circuit 53.The sense amplifiers SA are selected by a column decoder 52.

The row decoder 51 is controlled by a row address supplied from a rowcontrol circuit 61. The row control circuit 61 includes an addressbuffer 61 a that receives a row address supplied from the interface chipIF through the through silicon via TSV, and the row address that isbuffered by the address buffer 61 a is supplied to the row decoder 51.The address signal that is supplied through the through silicon via TSVis supplied to the row control circuit 61 through the input buffer B1through a TSV receiver 35 and a control logic circuit 63. The rowcontrol circuit 61 also includes a refresh counter 61 b. When aninternal refresh command is issued by the control logic circuit 63, arow address that is indicated by the refresh counter 61 b is supplied tothe row decoder 51.

The row decoder 51 includes a not-shown address comparison circuit,which compares the row address supplied from the row control circuit 61with addresses retained in a defective address latch circuit 56. Thedefective address latch circuit 56 is a circuit that latches defectiverow addresses read from the optical fuse circuit 55. The defectiveaddress latch circuit 56 includes a circuit that latches the defectiverow addresses read from the optical fuse circuit 55, as well as acircuit that latches defective row addresses read from the electricalfuse circuit 83. If the comparison by the row decoder 51 shows a matchof the addresses, a redundant word line included in the row redundancyarray 50 a is accessed instead of the word line that is designated bythe row address. If the addresses do not match, the word line designatedby the row address is simply accessed.

The optical fuse circuit 55 includes a plurality of fuse sets. The fusesets correspond to the respective plurality of redundant word lines inthe row redundancy array 50 a. That is, if a fuse set is programmed witha row address and an access to that row address is requested, then theredundant word line associated with that fuse set is accessed. Some ofthe fuse sets included in the optical fuse circuit 55 correspond tothose included in the electrical fuse circuit 83 on a one-to-one basis.Consequently, redundant word lines that are specified as replacing wordlines by some of the fuse sets included in the optical fuse circuit 55can also be specified as replacing word lines by fuse sets included inthe electrical fuse circuit 83. However, the optical fuse circuit 55 andthe electrical fuse circuit 83 will not conflict with each other. Aredundant word line is used as a replacing word line by either one of afuse set included in the optical fuse circuit 55 and a fuse set includedin the electrical fuse circuit 83.

The column decoder 52 is controlled by a column address supplied from acolumn control circuit 62. The column control circuit 62 includes anaddress buffer 62 a that receives a column address supplied from theinterface chip IF through the through silicon vias TSV. The columnaddress buffered in the address buffer 62 a is supplied to the columndecoder 52. The column control circuit 62 also includes a burst counter62 b that counts the burst length.

The column decoder 52 includes a not-shown address comparison circuit,which compares the column address supplied from the column controlcircuit 62 with addresses retained in a defective address latch circuit58. The defective address latch circuit 58 is a circuit that latchesdefective column addresses read from the optical fuse circuit 57. Thedefective address latch circuit 58 includes a circuit that latches thedefective column addresses read from the optical fuse circuit 57, aswell as a circuit that latches defective column addresses read from theelectrical fuse circuit 83. If the comparison by a column decoder 52shows a match of the addresses, a redundant bit line included in thecolumn redundancy array 50 b is accessed instead of the bit line that isdesignated by the column address. If the addresses do not match, the bitline designated by the column address is simply accessed. The bit linesare accessed by selecting the corresponding sense amplifiers SA in thesense circuit 53.

The optical fuse circuit 57 includes a plurality of fuse sets. The fusesets correspond to the respective plurality of redundant bit lines inthe column redundancy array 50 b. That is, if a fuse set is programmedwith a column address and an access to that column address is requested,then the redundant bit line associated with that fuse set is accessed.Some of the fuse sets included in the optical fuse circuit 57 correspondto those included in the electrical fuse circuit 83 on a one-to-onebasis. Consequently, redundant bit lines that are specified as replacingbit lines by some of the fuse sets included in the optical fuse circuit57 can also be specified as replacing bit lines by fuse sets included inthe electrical fuse circuit 83. Note that the optical fuse circuit 57and the electrical fuse circuit 83 will not conflict with each other. Aredundant bit line is used as a replacing bit line by either one of afuse set included in the optical fuse circuit 57 and a fuse set includedin the electrical fuse circuit 83.

The sense amplifier SA selected by the column decoder 52 is connected tothe data control circuit 54 through some amplifiers (sub-amplifiers ordata amplifiers or the like) which are not shown in the drawings.Thereby, read data of 8 bits (=prefetch number) for each I/O (DQ) isoutput from the data control circuit 54 at reading, and write data of 8bits is input to the data control circuit 54 at writing. The datacontrol circuit 54 and the interface chip IF are connected in parallelthrough a TSV buffer 27 and the through silicon via TSV. The datacontrol circuit 54 includes a test circuit 54 a. The test circuit 54 amakes a pass-fail determination in a test operation, and outputs theresult of the pass-fail determination as a determination signal P/F.

The control logic circuit 63 receives an internal command ICMD suppliedfrom the interface chip IF through the through silicon via TSV andcontrols the row control circuit 61 and the column control circuit 62,based on the internal command ICMD. The control logic circuit 63 isconnected to a layer address comparing circuit (chip informationcomparing circuit) 47. The layer address comparing circuit 47 detectswhether the corresponding core chip is target of access, and thedetection is performed by comparing the layer address EXA which is apart of the address signal supplied from the interface chip IF throughthe through silicon via TSV and a layer address LID (chip identificationinformation) set to the layer address generating circuit 46. The layeraddress EXA supplied from the interface chip IF is input to the corechips CC0 to CC7 through respective input receivers 49.

In the layer address generating circuit 46, unique layer addresses areset to the core chips CC0 to CC7, respectively, at initialization. Amethod of setting the layer addresses is as follows. First, after thesemiconductor device 10 is initialized, a minimum value (0, 0, 0) as aninitial value is set to the layer address generating circuits 46 of thecore chips CC0 to CC7. The layer address generating circuits 46 of thecore chips CC0 to CC7 are cascade-connected using the through siliconvias TSV of the type shown in FIG. 3B, and have increment circuitsprovided therein. The layer address (0, 0, 0) that is set to the layeraddress generating circuit 46 of the core chip CC0 of the uppermostlayer is transmitted to the layer address generating circuit 46 of thesecond core chip CC1 through the through silicon via TSV and isincremented. As a result, a different layer address (0, 0, 1) isgenerated. Hereinafter, in the same way as the above case, the generatedlayer addresses are transmitted to the core chips of the lower layersand the layer address generating circuits in the core chips incrementthe transmitted layer addresses. A maximum value (1, 1, 1) as a layeraddress is set to the layer address generating circuit of the core chipCC7 of the lowermost layer. Thereby, the unique layer addresses are setto the core chips CC0 to CC7, respectively.

The layer address generating circuit 46 is supplied with a defectivechip signal DEF2 from an inactivation circuit 36. The inactivationcircuit 36 is a circuit that is activated when a defective chip signalDEF1 is supplied from the defective chip information holding circuit 33of the interface chip IF through the through silicon vias TSV. As thedefective chip signal DEF1 is supplied to the individual core chips CC0to CC7 using the through silicon via TSV3 of the type shown in FIG. 3C,the defective chip signals DEF1 can be supplied to the core chips CC0 toCC7, individually. The defective chip signal DEF1 is activated when thecorresponding core chip is a defective chip. When the defective chipsignal DEF1 is activated, the layer address generating circuit 46transmits, to the core chip of the lower layer, a non-incremented layeraddress, not an incremented layer address. The defective chip signalDEF2 is also supplied to the control logic circuit 63. When thedefective chip signal DEF2 is activated, the control logic circuit 63 iscompletely halted. Thereby, the defective core chip performs neitherread operation nor write operation, even though an address signal or acommand signal is input from the interface chip IF.

An output of the control logic circuit 63 is also supplied to a moderegister 64. When an output of the control logic circuit 63 shows a moderegister set, the mode register 64 is updated by an address signal.Thereby, operation modes of the core chips CC0 to CC7 are set.

Each of the core chips CC0 to CC7 has an internal voltage generatingcircuit 72. The internal voltage generating circuit 72 is provided withpower supply potentials VDD and VSS. The internal voltage generatingcircuit 72 receives these power supply potentials and generates variousinternal voltages. As the internal voltages that are generated by theinternal voltage generating circuit 72, an internal voltage VPERI (≈VDD)for operation power of various peripheral circuits, an internal voltageVARY (<VDD) for an array voltage of the memory cell array 50, and aninternal voltage VPP (>VDD) for an activation potential of the word lineWL are included. In each of the core chips CC0 to CC7, a power-ondetecting circuit 71 is also provided. When the supply of power isdetected, the power-on detecting circuit 71 resets various internalcircuits.

The above description is the basic circuit configuration of the corechips CC0 to CC7. In the core chips CC0 to CC7, the front end unit foran interface with the external device is not provided. Therefore thecore chip cannot operate as a single chip in principle. However, if thecore chip never operates as the single chip, an operation test of thecore chip in a wafer state may not be performed. This means that thesemiconductor memory device 10 cannot be tested, before the interfacechip and the plural core chips are fully assembled. In other words, theindividual core chips are tested when testing the semiconductor memorydevice 10. When unrecoverable defect exists in the core chips, theentire semiconductor memory device 10 is led to be unavailable. In thisembodiment, in the core chips CC0 to CC7, a portion of a pseudo frontend unit, for testing, that includes some test pads TP and a test frontend unit of a test command decoder 65 is provided, and an address signaland test data or a command signal can be input from the test pads TP. Itis noted that the test front end unit is provided for a simple test in awafer test, and does not have all of the front end functions in theinterface chip. For example, since an operation frequency of the corechips is lower than an operation frequency of the front end unit, thetest front end unit can be simply realized with a circuit that performsa test with a low frequency.

Kinds of the test pads TP are almost the same as those of the externalterminals provided in the interposer IP. Specifically, the test padsinclude a test pad TP1 to which a clock signal is input, a test pad TP2to which an address signal is input, a test pad TP3 to which a commandsignal is input, a test pad TP4 for input/output test data, a test padTP5 for input/output a data strobe signal, and a test pad TP6 for apower supply potential.

A common external command (not decoded) is input at testing. Therefore,the test command decoder 65 is also provided in each of the core chipsCC0 to CC7. Because serial test data is input and output at testing, atest input/output circuit 29 and a test FIFO circuit 28 are alsoprovided in each of the core chips CC0 to CC7. At testing, a DFT circuit66 is used which is included in each of the core chips CC0 to CC7.

This is the entire configuration of the semiconductor device 10. Becausein the semiconductor device 10, the 8 core chips of 1 Gb are laminated,the semiconductor device 10 has a memory capacity of 8 Gb in total.Because the chip select signal /CS is input to one terminal (chip selectterminal), the semiconductor memory device is recognized as a singleDRAM having the memory capacity of 8 Gb, in view of the controller.However, a memory capacity of the core chip is not restricted inparticular.

Next, a method of replacing defective cells included in the core chipsCC0 to CC7 will be described.

The replacement of defective cells is performed twice in the process ofmanufacturing the semiconductor device 10. The first replacement isperformed in a wafer process, and the second an assembly process. Thereplacement in the wafer process is performed by using the optical fuses55 and 57 in order to repair defects that occur in the wafer process.The replacement in the assembly process is performed by using theelectrical fuse circuit 83 in order to repair defects that occur in theassembly process. In other words, the replacement in the wafer processstores defective addresses into the core chips CC0 to CC7 themselves.The replacement in the assembly process stores defective addresses intothe interface chip IF.

FIG. 6 is a flowchart for explaining the method of replacing defectivecells included in the core chips CC0 to CC7.

At first, the core chips CC0 to CC7 in a wafer state are subjected to anoperation test to detect defective addresses (step S10). The defectiveaddresses detected are analyzed in a tester outside the semiconductordevice 10, whereby replacement data is determined. The replacement datarefers to information that identifies the word lines or bit lines to bereplaced and the word lines or bit lines to replace. The word lines orbit lines to be replaced are identified by row addresses or columnaddresses. The word lines or bit lines to replace are identified by theaddresses of fuse sets to be used in the optical fuse circuits 55 and57.

Next, the optical fuse circuits 55 and 57 are programmed based on thereplacement data (step S11). Specifically, laser beam irradiation isperformed by using a laser trimmer, whereby predetermined fuse setsincluded in the optical fuse circuits 55 and 57 are programmed with rowaddresses that represent the word lines to be replaced or columnaddresses that represent the bit lines to be replaced. The completion ofthe replacement operation in the wafer process is followed by wafersingulation (step S12). Meanwhile, the electrical fuse circuit 83 in theinterface chip IF is fabricated in a step separate from the settingsteps of the core chips CC0 to CC7 (step S13).

Next, the separated pieces of the core chips CC0 to CC7 and theinterface chip IF are stacked on each other and packaged as shown inFIG. 6 (step S14). After the packaging, the second operation test isperformed to detect defective addresses (step S15). The first operationtest performed in the wafer state and the replacement of defective cellsbased on the operation test ensure that all the addresses of the corechips CC0 to CC7 to be stacked are normally accessible. However, newdefective addresses may occur due to load during packaging and the loadof a burn-in test. The second operation test is performed to detect andrepair such new defective addresses that occur after the end of thefirst operation test.

Next, the electrical fuse circuit 83 is programmed based on thedefective addresses detected (step S16). Specifically, an electricalfuse controller (to be described later) included in the electrical fusecircuit 83 is used to apply a high voltage, whereby the fuse setsincluded in the electrical fuse circuit 83 are programmed with rowaddresses that represent the word lines to be replaced or columnaddresses that represent the bit lines to be replaced. This completesthe series of replacement operations, and the semiconductor device 10 isshipped as a confirming product.

FIG. 7 is a flowchart for explaining the operation of steps S15 and 16shown in FIG. 6 in more detail.

At first, one of the core chips CC0 to CC7 is selected (step S20), andan operation test is performed thereon (step S21). In the operationtest, the data control circuit 54 (test circuit 54 a) in that core chipCC0 to CC7 makes pass-fail determinations. The resulting determinationsignal P/F is transferred to the analysis circuit 82 in the interfacechip IF through the through silicon vias TSV1, and analyzed by theanalysis circuit 82 (step S22). The analysis circuit 82 analyzes thedefective addresses to generate replacement data so that all thedefective cells found can be replaced with a smaller number of redundantword lines or redundant bit lines. The replacement data includesinformation on replacing word lines or bit lines, which are identifiedin terms of the addresses of fuse sets to be used in the electrical fusecircuit 83.

If the analysis shows that the replacement is not possible even by usingall the fuse sets (step S23: NO), the semiconductor device 10 is handledas a defective product (step S27). Even if the replacement is possibleby using fuse sets in the electrical fuse circuit 83, the semiconductordevice 10 may also be handled as a defective product (step S27) when thefuse sets to be used in the electrical fuse circuit 83 are alreadyassigned to the used fuse sets in the optical fuse circuits 55 and 57(step S24: NO). If neither is the case, predetermined fuse sets in theelectrical fuse circuit 83 are programmed with row addresses thatrepresent the word lines to be replaced or column addresses thatrepresent the bit lines to be replaced (step S25). As a result, newdefective addresses occurring in the core chip are repaired.

Such an operation is performed on all the core chips CC0 to CC7 inorder. If the foregoing operation is completed on all the core chips CC0to CC7 (step S26: YES), the series of replacement operations arecompleted and the semiconductor device 10 is shipped as a conformingproduct.

FIG. 8 is a flowchart for explaining the operation of loading thereplacement data programmed in the electrical fuse circuit 83.

The operation of loading the replacement data is performed in responseto when the reset signal /RESET supplied to the command terminal 12 fchanges to a high level (step S31). When the reset signal /RESET changesto the high level, the load circuit 85 included in the interface chip IFis activated to read the replacement data programmed in the electricalfuse circuit 83 (step S32). The replacement data read from theelectrical fuse circuit 83 is serial-converted by the serializer 84, andtransferred to each of the core chips CC0 to CC7 through the throughsilicon vias TSV1 (step S33). When the serializer 84 transfers thereplacement data, the layer address buffer 48 simultaneously transfers alayer address EXA. The replacement data, which is supplied in common tothe core chips CC0 to CC7, is thereby enabled only for the core chipthat is designated by the layer address EXA. The replacement data islatched into the defective address latch circuits 56 and 58 included inthat core chip. When all the pieces of replacement data are transferredto the respective corresponding core chips CC0 to CC7, the series oftransfer operations are completed (step S34).

FIG. 9 is a block diagram showing the configuration of the electricalfuse circuit 83 in more detail.

As shown in FIG. 9, the electrical fuse circuit is provided for eachbank. Since the present embodiment has an 8-bank configuration, theelectrical fuse circuit 83 is divided into eight electrical fusecircuits 83-0 to 83-7, which correspond to bank 0 to bank 7,respectively. The electrical fuse circuits 83-0 to 83-7 have the samecircuit configuration. FIG. 9 representatively shows only the circuitconfiguration of the electrical fuse circuit 83-0.

The electrical fuse circuit 83-0 includes a plurality of fuse sets 83-00to 83-07 which are allocated to the core chips CC0 to CC7, respectively.The fuse sets 83-00 to 83-07 each include a plurality of fuse setsintended for row addresses and column addresses. The fuse sets areprovided with respective corresponding control circuits 83 a, which readand write the fuse sets under the control of an electrical fusecontroller 83 b. Data to be written to the fuse sets and data read fromthe fuse sets are transmitted and received through a transfer controlcircuit 83 c.

Each fuse set includes a plurality of electrical fuses. Electrical fusesare electrically-writable memory elements, preferably a nonvolatile andirreversible one-time ROM. For a one-time ROM, it is preferred to useantifuse elements in which data is stored in terms of the presence orabsence of a dielectric breakdown (breakdown of an insulating film) dueto application of a high voltage.

The data read through the transfer control circuit 83 c isserial-converted by the serializer 84 before transferred to the corechips CC0 to CC7 through the through silicon vias TSV. The data to bewritten to the electrical fuse circuit 83 is supplied from the controllogic 32 and the analysis circuit 82, and programmed into predeterminedfuse sets under the control of the electrical fuse controller 83 b. Theelectrical fuse controller 83 b thus functions as a programming circuitthat programs the electrical fuse sets.

FIG. 10 is a block diagram showing the configuration of the defectiveaddress latch circuit 56 in more detail.

As shown in FIG. 10, the defective address latch circuit 56 includes alatch circuit 56 a that latches replacement data read from an opticalfuse circuit 55, and a latch circuit 56 b that latches replacement dataread from the electrical fuse circuit 83. A data control circuit 56 cand a data latch circuit 56 d are arranged in the stage prior to thelatch circuit 56 b. Under the control of the circuits 56 c and 56 d, thereplacement data transferred from the interface chip IF through thethrough silicon vias TSV is latched into the latch circuit 56 b.

The output of the latch circuit 56 a and the output of the latch circuit56 b are supplied to a select circuit 56 e. The select circuit 56 e is acircuit that selects either one of the outputs of the latch circuit 56 aand the latch circuit 56 b. The replacement data selected is supplied toa row decoder 51. The select circuit 56 e makes the selection based onflag information to be described later. The row decoder 51 includes anaddress comparison circuit 51 a, which compares the replacement dataselected by the select circuit 56 e with an access-requested rowaddress. If the two match, a redundant word line included in a rowredundancy array 50 a is accessed instead of the word line that isdesignated by the row address. If the addresses do not match, the wordline designated by the row address is simply accessed.

The defective address latch circuit 58 on the column side has the samecircuit configuration as that of the defective address latch circuit 56described above. Redundant description will thus be omitted.

As mentioned above, the replacement data transferred from the interfacechip IF is supplied in common to the core chips CC0 to CC7. The corechips CC0 to CC7 therefore need the layer address EXA in order todetermine whether or not to accept the transferred replacement data. Forthat purpose, as shown in FIG. 11, the replacement data and the layeraddress EXA are simultaneously transferred to the core chips CC0 to CC7.The replacement data supplied in common to the core chips CC0 to CC7 isthereby enabled only for the core chip that is designated by the layeraddress EXA. More specifically, the data control circuit 56 c and thedata latch circuit 56 d are activated to perform the processing ofwriting the transferred replacement data into the latch circuit 56 bonly when the layer address EXA matches the layer address LID unique toeach core chip CC0 to CC7. The series of transfer operations areperformed in synchronization with the internal clock signal ICLK whichis generated in the interface chip IF.

FIG. 12 is a block diagram showing the configuration of the electricalfuse circuit 83 and the defective address latch circuit 56 in moredetail.

As has been described, the electrical fuse circuit 83 is divided intothe electrical fuse circuits 83-0 to 83-7 by bank. The electrical fusecircuits 83-0 to 83-7 each include a plurality of fuse sets 83-00 to83-07 which are allocated to the core chips CC0 to CC7, respectively. Asshown in FIG. 12, the electrical fuse set 83-00 includes (X+1) fusesets, whereby (X+1) row addresses (or column addresses) can be stored.

As shown in FIG. 12, each defective address latch circuit 56 includes(N+1) latch circuits 56 a and (X+1) latch circuits 56 b. The (N+1) latchcircuits 56 a correspond to zeroth to Nth optical fuse sets,respectively. Of these, the latch circuits 56 a corresponding to thezeroth to (N−1−X)th optical fuse sets have no latch circuit 56 b to bepaired with, and thus have no corresponding select circuit 56 e.

On the other hand, the latch circuits 56 a corresponding to the (N−X)thto Nth optical fuse sets have latch circuits 56 b to be paired with.Specifically, the latch circuits 56 b corresponding to the Xth to zerothelectrical fuse sets are allocated to the (N−X)th to Nth optical fusesets, respectively. Select circuits 56 e are provided for such latchcircuits 56 a and 56 b, so that the outputs of either ones of the latchcircuits 56 a and 56 b are selected. Replacement data transferred fromthe interface chip IF is latched into specified latch circuits 56 bunder the control of a fuse select circuit 56 s.

The outputs of the latch circuits 56 a and 56 b are supplied to theaddress comparison circuits 51 a. If an output matches an access-requestaddress, the corresponding redundant word line RWL is accessed.

FIG. 13 is a diagram for explaining the relationship between the orderof selection of the optical fuse circuits 55 and the order of selectionof the electrical fuse circuit 83.

As has been described, the optical fuse circuits are programmed in stepS11 shown in FIG. 6. The electrical fuse circuit 83 is programmed instep S16 shown in FIG. 6. That is, the optical fuse circuits areprogrammed first, and fuse sets remaining unused in step S11 are used bythe electrical fuse circuit 83 for alternative use. In such aconfiguration, no conflict is allowed between the redundant word linesthat are selected by the optical fuse circuits 55 and the redundant wordlines that are selected by the electrical fuse circuit 83. In order toavoid such a conflict and in order for the electrical fuse circuit 83 touse the remaining fuse sets for alternative use more efficiently, thepresent embodiment is configured so that, as shown in FIG. 13, theoptical fuse circuits 55 are programmed by using the optical fuse setsfrom the zeroth in succession (arrow LF). On the other hand, theelectrical fuse circuit 83 is programmed by using the electrical fusesets from the zeroth, which is paired with the Nth optical fuse set, insuccession (arrow AF). This makes it possible for the electrical fusecircuit 83 to efficiently use the remaining fuse sets for alternativeuse.

FIG. 14 is a circuit diagram showing an example of the addresscomparison circuit 51 a and the select circuit 56 e. The circuit exampleshown in FIG. 14 is suitably applied to the row side.

The example shown in FIG. 14 includes 14 latch circuits 56 a and 14latch circuits 56 b which correspond to the bits A0 to A13 of a rowaddress, respectively. The outputs of the latch circuits are comparedwith the respective corresponding bits of the row address by the EXNORcircuits. The outputs of the EXNOR circuits corresponding to the latchcircuits 56 a are collected by an AND gate circuit and output as anoptical fuse hit signal LFHIT. Similarly, the outputs of the EXNORcircuits corresponding to the latch circuits 56 b are collected by anAND gate circuit and output as an electrical fuse hit signal AFHIT.

The optical fuse hit signal LFHIT and the electrical fuse hit signalAFHIT are supplied to the select circuit 56 e, and either one of thesignals is selected by a select signal SEL. The signal selected isoutput as a redundancy determination signal HIT. The select signal SELis generated by an AND gate circuit 56 f. The AND gate circuit 56 f issupplied with the output of a latch circuit 56 ae that latches anoptical fuse enable signal LFEN, and the output of a latch circuit 56 bethat latches an electrical fuse enable signal AFEN. The electrical fuseenable signal AFEN corresponds to the first flag information FL1 shownin FIG. 1, and indicates whether the corresponding electrical fuse setis enabled or not, i.e., whether used or not. The optical fuse enablesignal LFEN corresponds to the second flag information FL2 shown in FIG.1, and indicates whether the corresponding optical fuse set is enabledor not, i.e., whether used or not.

The optical fuse enable signal LFEN turns to a high level when theoptical fuse set is used. The electrical fuse enable signal AFEN turnsto a high level when the electrical fuse set is used. Consequently, whenthe optical fuse set is in use, the select signal SEL remains at a lowlevel. In such a case, the select circuit 56 e selects the optical fusehit signal LFHIT. On the other hand, when the optical fuse set is not inuse and the electrical fuse set is in use, the select signal SEL turnsto a high level and the select circuit 56 e selects the electrical fusehit signal AFHIT.

FIG. 15 is a circuit diagram showing another example of the addresscomparison circuit 51 a and the select circuit 56 e. The circuit exampleshown in FIG. 15 is suitably applied to the column side.

The example shown in FIG. 15 includes seven latch circuits 56 a andseven latch circuits 56 b which correspond to the bits Y3 to Y9 of acolumn address, respectively. Unlike the circuit example shown in FIG.14, the select circuit 56 e is provided for each bit. The outputs of theseven select circuits 56 e are compared with the respectivecorresponding bits by the EXNOR circuits. The outputs of the EXNORcircuits are collected by an AND gate circuit 56 g and output as aredundancy determination signal HIT.

The select signal SEL is supplied in common to the seven select circuits56 e. The select signal SEL is generated by the AND gate circuit 56 f.As has been described with reference to FIG. 14, the select signal SELremains at the low level when the optical fuse set is in use. In such acase, the select circuits 56 e select the optical-fuse side. On theother hand, when the optical fuse set is not in use and the electricalfuse set is in use, the select signal SEL turns to the high level andthe select circuits 56 e select the electrical-fuse side.

The output of the latch circuit 56 ae that latches the optical fuseenable signal LFEN and the output of the latch circuit 56 be thatlatches the electrical fuse enable signal AFEN are supplied to an ORgate circuit 56 h. The output of the OR gate circuit 56 h is input tothe AND gate circuit 56 g. Consequently, when neither of the opticalfuse set and the electrical fuse set is in use, the redundancydetermination signal HIT is fixed to an inactive state.

It is apparent that the present invention is not limited to the aboveembodiments, but may be modified and changed without departing from thescope and spirit of the invention.

The technical concept of the present invention may be applied to asemiconductor device that includes a core chip or core chips pertainingto volatile and nonvolatile memory cells and an interface chip forcontrolling the core chip(s). It should be noted that the forms of thecircuits in the circuit blocks disclosed in the drawings and othercircuits for generating control signals are not limited to the circuitforms disclosed in the embodiment.

The technical concept of the voltage level shift circuit of the presentinvention may be applied to various semiconductor devices. For example,the present invention may be applied to semiconductor products ingeneral, including functions as CPUs (Central Processing Units), MCUs(Micro Control Units), DSPs (Digital Signal Processors), ASICs(Application Specific Integrated Circuits), ASSPs (Application SpecificStandard Products), and memories. Examples of the product types of thesemiconductor devices to which the present invention is applicableinclude an SOC (System On Chip), MCP (Multi Chip Package), and POP(Package On Package). The present invention may be applied tosemiconductor devices that have any of such product types and packagetypes.

When the transistors are field effect transistors (FETs), various FETsare applicable, including MIS (Metal Insulator Semiconductor) and TFT(Thin Film Transistor) as well as MOS (Metal Oxide Semiconductor). Thedevice may even include bipolar transistors.

In addition, an NMOS transistor (N-channel MOS transistor) is arepresentative example of a first conductive transistor, and a PMOStransistor (P-channel MOS transistor) is a representative example of asecond conductive transistor.

Many combinations and selections of various constituent elementsdisclosed in this specification can be made within the scope of theappended claims of the present invention. That is, it is needles tomention that the present invention embraces the entire disclosure ofthis specification including the claims, as well as various changes andmodifications which can be made by those skilled in the art based on thetechnical concept of the invention.

What is claimed is:
 1. A semiconductor device comprising: an externalterminal; a plurality of first chips each of which includes a pluralityof memory cells; a second chip that communicates with outside of thesemiconductor device through the external terminal and controls theplurality of first chips; and a plurality of internal wirings coupledbetween the first chips and the second chip, wherein the plurality offirst chips each communicates with the second chip through the pluralityof internal wirings, the second chip includes a first fuse, and each ofthe first chips further includes: a second fuse; a first latch circuitthat stores information in the second fuse; a second latch circuit thatstores information in the first fuse supplied from the second chipthrough the internal wirings; a select circuit that selects one of theinformation stored in the first and second latch circuits; and a firstcontrol circuit that generates a redundancy determination signal basedon the information selected by the select circuit.
 2. The semiconductordevice as claimed in claim 1, wherein the second chip further includes afirst output circuit that outputs the information on the first fuse toat least one of the internal wirings, and each of the first chipsfurther includes a first input circuit that receives the information onthe first fuse supplied via at least one of the internal wirings.
 3. Thesemiconductor device as claimed in claim 2, wherein the second chipstores first flag information that indicates whether or not the firstfuse is programmed, each of the first chips further includes a thirdlatch circuit that stores the first flag information supplied through atleast one of the internal wirings, and the select circuit selects one ofthe information stored in the first and second latch circuits based onthe first flag information stored in the third latch circuit.
 4. Thesemiconductor device as claimed in claim 3, wherein the first outputcircuit of the second chip further outputs the first flag information tothe corresponding at least one of the internal wirings, and the firstinput circuit of each of the first chips further receives the first flaginformation through the corresponding at least one of the internalwirings.
 5. The semiconductor device as claimed in claim 2, wherein eachof the first chips includes a circuit to be capable to output chipidentification information to distinguish each of the first chips, thefirst output circuit of the second chip further outputs layerinformation to the internal wirings along with the information on thefirst fuse, and the first input circuit of each of the first chipssupplies the information in the first fuse sent from the second chip tothe second latch circuit when the layer information coincides with thechip identification information.
 6. The semiconductor device as claimedin claim 1, wherein the second chip further includes a programmingcircuit coupled to the first fuse and programming the address to thefirst fuse.
 7. The semiconductor device as claimed in claim 3, whereinthe second chip further includes another first fuse having a samestructure as that of the first fuse and stores the first flaginformation, and each of the first chips further includes another secondfuse having a same structure as that of the second fuse and storessecond flag information that indicate whether or not the second fuse isprogrammed.
 8. The semiconductor device as claimed in claim 1, whereinthe first fuse comprises a onetime ROM.
 9. A semiconductor devicecomprising: an external signal terminal; a plurality of first chips eachof which includes a plurality of memory cells; and a second chip coupledto the external signal terminal to communicate with outside of thesemiconductor device and controlling the plurality of first chips,wherein the first chips are electrically coupled to the second chip, atleast one of the first chips includes a plurality of through electrodespenetrating through a corresponding one or ones of the first chips, thesecond chip includes a first fuse configured to be capable of storing anaddress of a defective memory cell corresponding one or ones of thememory cells included in any of the first chips, each of the first chipsfurther includes: a second fuse configured to be capable of storing anaddress of a defective memory cell corresponding one or ones of thememory cells included in any of the first chips; a redundant cellconfigured to be capable of being electrically replaced by the defectivememory cell associated with the first or second fuses; a select circuitthat selects one of information of the first and second fuses; and anaccess control circuit that accesses the redundant cell based on theinformation selected by the select circuit.
 10. The semiconductor deviceas claimed in claim 9, wherein the first fuse is electrically coupled tothe select circuit via one or ones of the through electrodes.
 11. Thesemiconductor device as claimed in claim 10, wherein each of the firstchips further includes: a first latch circuit electrically coupledbetween the second fuse and the select circuit; and a second latchcircuit electrically coupled between the first fuse and the selectcircuit, wherein the select circuit selects one of information of thefirst and second latch circuits.
 12. The semiconductor device as claimedin claim 9, wherein the second chip further includes a programmingcircuit coupled to the first fuse and programming the address to thefirst fuse.
 13. The semiconductor device as claimed in claim 9, whereineach of the first chips further includes a third fuse configured to becapable of storing an address of a defective memory cell correspondingone or ones of the memory cells included in any of the first chips, noneof the first fuse included in the second chip is allocated to the thirdfuse.
 14. The semiconductor device as claimed in claim 9, wherein thefirst fuse comprises a onetime ROM.
 15. The semiconductor device asclaimed in claim 9, wherein the first fuse comprises an antifuse elementthat irreversibly stores information by breakdown of an insulating film.16. The semiconductor device as claimed in claim 1, wherein the firstfuse comprises an antifuse element that irreversibly stores informationby breakdown of an insulating film.
 17. The semiconductor device asclaimed in claim 1, wherein the first fuse includes an electrical fuse,and the second fuse includes an optical fuse.
 18. The semiconductordevice as claimed in claim 1, wherein the first fuse includes anelectrical fuse, and the second fuse includes an optical fuse.
 19. Asemiconductor device comprising: an external terminal; a first wiringand a second wiring; a first chip; and a second chip coupled to theexternal terminal to communicate with outside of the semiconductordevice via the first wiring, the second chip coupled to the first chipvia the second wiring, wherein the first chip includes: a memory cell; aredundant cell configured to be capable of being electrically replacedby the memory cell; and a second fuse configured to be capable ofstoring information, the second chip includes: a first fuse configuredto be capable of storing information; a select circuit coupled to thefirst and second fuses and selecting one of information of the first andsecond fuses; and an access control circuit coupled to the selectcircuit and the redundant cell, and accessing the redundant cell basedon the information selected by the select circuit.
 20. The semiconductordevice as claimed in claim 19, wherein the first fuse includes anelectrical fuse.
 21. The semiconductor device as claimed in claim 19,wherein the first fuse includes an antifuse element that irreversiblystores information by breakdown of an insulating film.
 22. Thesemiconductor device as claimed in claim 19, wherein each of the memorycell and the redundant cell comprises a memory cell of a synchronousdynamic random access memory.
 23. The semiconductor device as claimed inclaim 19, wherein one of the first and second chips includes a throughelectrode that penetrates a substrate of a corresponding one of thefirst chip or second chip, the through electrode is electrically coupledto the second wiring.
 24. The semiconductor device as claimed in claim19, wherein each of the first and second chips includes a throughelectrode that penetrates a substrate of a corresponding one of thefirst chip and second chips.
 25. The semiconductor device as claimed inclaim 1, wherein the memory cell comprises a memory cell of asynchronous dynamic random access memory.
 26. The semiconductor deviceas claimed in claim 9, wherein each of the memory cell and the redundantcell comprises a memory cell of a synchronous dynamic random accessmemory.